Hello everyone, i want to use the 3D printer for a project for my school, but when i try to realize something the fans doesn't work, so i have to stop it because i don't want to have more problems. I designed my project with Freecad and exported the file in G-code from slic3r. The connections are ok so we don't understand where's the problem, since when we try to make the simple test all the printer works properly, but the problems come when we try to make something else.

What layer are you stopping on? The PLA profile that kengdahl generated has the cooling fan turned off for the first layer. If you aren't using slic3r in "expert" mode this value doesn't show; it is on the filament configuration page when expert mode is turned on. Based on your description this sounds like it may be worth checking.